The present disclosure relates to an inductor and a manufacturing method thereof.
An inductor, an important passive element configuring an electronic circuit together with a resistor and a capacitor, is used in various systems and components such as a low noise amplifier, a mixer, a voltage controlled oscillator, a matching coil, and the like.
Such an inductor may be classified as, for example, a wire wound inductor, a multilayer inductor, a thin film inductor, or further type of inductor, according to the structure thereof.
Among these types of inductor, wire wound inductors are commonly formed by winding a coil around a ferrite core, or the like.
In such a wire wound inductor, since stray capacitance may be generated between coil portions, in order to obtain a high degree of inductance, an amount of coil turns need to be increased, but in a case in which the turns of the coil are increased, high frequency characteristics may be deteriorated.
A multilayer inductor may be formed by stacking a plurality of ceramic sheets.
Such a multilayer inductor may have a structure in which a coil shaped metal pattern is formed on each of the ceramic sheets included therein, and the metal patterns may have a single electrical connection while being sequentially connected to each other by a plurality of conductive vias provided in each of the ceramic sheets.
The multilayer inductor is suitable for mass production due to having such a structure, and when being compared with wire wound inductors, multilayer inductors may have excellent high frequency characteristics.
However, in multilayer inductors, since a saturation magnetization value of materials configuring the metal pattern is low, and in the case of manufacturing compact multilayer inductors, the amount of stacked metal patterns may be limited, while direct current (DC) bias characteristics may be decreased, such that a sufficient amount of current may not be obtained.
A thin film inductor may be manufactured by forming a thin film shaped conductive coil on a coil support layer.
Such a thin film inductor may use a material having a saturation magnetization value higher than that of the multilayer inductor, and in the case of manufacturing compact thin film inductors, there is no limitation on a height thereof, and it may be easy to form an internal circuit pattern. Therefore, recently, research into thin film inductors has been actively conducted.
Particularly, as display device screens are increased in size in accordance with the implementation of high degrees of performance in portable devices such as smartphones, tablet personal computers (PCs), and the like, the speed of an accelerated processing unit (APU) may be increased, while power consumption may be increased due to the use of a multi-core processor, or the like. Therefore, in the case of a thin film inductor mainly used in a DC-DC converter, a noise filer, or the like, a thin film inductor capable of implementing high inductance and low DC resistance has also been demanded.
In addition, since the miniaturization and thinning of various electronic devices have progressed in accordance with the development of information technology (IT), thin film inductors used in such electronic devices are also required to be miniaturized and thinned.
Meanwhile, recently, in order to improve performance of thin film inductors, technology in which a magnetic body is formed on a coil support layer together with a thin film conductive coil has been developed.
Performance of such thin film inductors is significantly dependent on magnetic properties of soft ferrite, or the like, used to configure bodies thereof.
A magnetic body used in a thin film inductor needs to have a sufficient degree of permittivity in a high frequency region at the time of the application thereof at a high frequency, needs not to be thermally and mechanically degraded during a manufacturing process of the inductor, and needs to be insulated from the conductive coil. Therefore, an insulation layer is formed between the magnetic body and the conductive coil.
In a thin film inductor according to the related art, an insulation layer was formed between the magnetic body and the conductive coil using a vacuum impregnation method, or the like.
However, such a method of forming the insulation layer may cause a defect such as a phenomenon in which the insulating layer may do not completely fill gaps in a conductive coil and thus, portions of the gaps may remain empty in the case of a small product, that is, a defect in which voids are generated in the gaps of the conductive coil.
That is, in the case of performing photocuring using a dry film in a thin film inductor according to the related art, an amount of an insulating margin portion, sufficient to cause photocuring up to a lower portion of the conductive coil having a thickness of 100 μm or more may be required. However, inductance of the inductor may be reduced in accordance with an increase in the insulating margin portion. Thus, in the case of forming an insulating layer through coating a surface of the conductive coil, since voids are generated in the gaps of the conductive coil, reliability may be significantly deteriorated under high temperature and high moisture conditions.